Tools

The MCP server exposes 20 core tools for the common flows plus one generated tool per API endpoint. Connect a client on the setup page, then call tools/list for the catalog your client sees.

First call

tools/list returns the tools the server offers a client, each with its JSON Schema. It needs no credential:

curl https://mcp.zernio.com/mcp \
  -X POST \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{"jsonrpc": "2.0", "method": "tools/list", "id": 1}'

The reply is one server-sent event whose data: line carries the JSON-RPC result. Response (200), trimmed to one tool:

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "tools": [
      {
        "name": "media_check_upload_status",
        "title": "Check upload status and get file URLs",
        "description": "Check the status of an upload token and get uploaded file URLs.",
        "inputSchema": {
          "type": "object",
          "properties": {
            "token": {
              "type": "string",
              "description": "The upload token from media_generate_upload_link (required)"
            }
          },
          "required": ["token"],
          "additionalProperties": false
        },
        "annotations": {
          "readOnlyHint": true,
          "destructiveHint": false,
          "openWorldHint": false
        }
      }
    ]
  }
}

That list is the core tools plus the everyday endpoints. Every other tool stays callable through search_tools and call_tool, described under how it behaves.

Core tools

The 20 hand-written tools take arguments shaped for an assistant (a platform name, minutes from now) and resolve the account for you:

Every write tool below refuses an ambiguous account instead of picking one; see how it behaves.

posts_create

Creates a post as a draft, scheduled, or published now. The two booleans pick the mode:

posts_publish_now

posts_create with publish_now=true.

posts_cross_post

Posts the same content to several platforms at once. To target two accounts on the same platform in one call, repeat the platform: platforms="twitter,twitter", account_ids="66b2e19d8c3f5a7e9d0b1c2d,66b2e19d8c3f5a7e9d0b1c2e".

posts_list

posts_get / posts_delete / posts_retry

posts_update

Only draft, scheduled and failed posts can be updated.

media_generate_upload_link

Takes no parameters. Returns an upload URL for the user to open in a browser, plus the token that media_check_upload_status polls and its expiry; see media uploads go through a browser link.

media_check_upload_status

The reply is pending while the user has not uploaded, expired when the link timed out, or completed with the filename, type, size and URL of each file and the comma-separated media_urls value to pass to posts_create.

docs_search

Searches these docs and returns the 5 best-matching sections, each with its heading and its text, so the assistant can answer a question about the API without leaving your client.

Generated tools

One tool per API endpoint, generated from the OpenAPI spec, so new endpoints appear as they ship. Names follow {category}_{operation}: the listAdCampaigns endpoint becomes ad_campaigns_list_ad_campaigns. Each tool maps 1:1 to an API reference operation, where the request and response schemas live, and the argument names are the snake_case form of the fields documented there.

The names are not retyped on this page. Call tools/list for the ones your client sees, and search_tools for the rest.

One generated tool is worth naming next to its core twin. posts_create_post mirrors the full createPost REST surface, so use it instead of posts_create for per-target customisation the core tool does not expose: customContent (a different caption per platform), customMedia (different attachments per target), a per-target scheduledFor, or platformSpecificData (TikTok privacy, YouTube category). Its platforms argument is an array of objects with platform, accountId and any per-target overrides. Available in zernio-sdk 1.4.0 and later.

How it behaves

search_tools and call_tool load the long tail on demand

Your client never loads every tool at once. tools/list returns about 50: the 20 core tools plus the everyday posting, queue, validation, account-health, analytics and engagement tools. The rest sit behind two tools: search_tools, a full-text search over the catalog ("send a WhatsApp template", "TikTok insights", "pause a campaign") that returns the best matches with their schemas, and call_tool, which invokes any tool the search found. A tool such as whatsapp_flows_publish_whats_app_flow costs no context until the assistant needs it, and there is nothing to configure.

Write tools refuse an ambiguous account

When you have more than one account on a platform, posts_create, posts_publish_now and posts_cross_post need account_id (or profile_id) to pick one. Without it they return an error listing the candidate account ids instead of picking one silently; the assistant calls accounts_list and retries. Available in zernio-sdk 1.4.0 and later.

Media uploads go through a browser link

An AI client cannot read files on your computer, so media reaches the server through a browser upload:

Accepted file types are JPG, PNG, WebP and GIF images, MP4, MOV, AVI, WebM and M4V videos, and PDF documents, up to 5 GB per file.

Related

• MCP: the first call from a client, and the tools/call request an agent sends.
• Setup: per-client configuration and the local server.
• Create post: the REST operation behind posts_create and posts_create_post.
• Media uploads: size and format limits per platform.
• Python SDK: the package the server ships in.